Pumping mechanism



April 7, 1953 s. HAUGDAHL PUMPING MECHANISM Filed Aug. 12, 1948 6 A n U H T M W 7% 0 w 1 5 v. 8 M 3 w Ml 4 l/ Z I/ 4 Z z I z n IH\\\\ MN 0 Z A 43 4 I a x 3 Patented Apr. 7, 1953 UNITED STATES PATENT OFFICE PUMPING MECHANISM Sigurd Haugdahl, Jacksonville, Fla., assignor', by mesne assignments, to Haugclahl, Inc., Daytona Beach, Fla., a corporation Application August 12, 1948,'Serial No. 43,894

1 Claim. 1

This: invention relates to a fluid pumping mechanism and more particularly to a pressure compensating rotary vane type pump of' a character to maintain a predetermined fluid pressure irrespective of variation in speed or delivery.

In known pumps of this character wherein "pressure is automatically maintained by varying the eccentricity of a pivoted pumping cylinder through pressure conditions, diificulty has been experienced in maintaining the pressure substancylinder. I I I It is, therefore, the object of this invention to provide a pump of this general character which will remain in constant balance and eliminate objectionable fluctuations, being positively and rapidly responsive'to the effect of fluid pressure variations, or to any slight change in fluid pressure actin to control the displacement of the pump. This is accomplished by the pumping cylinder having its pivotal bearing located offcenter, oras herein shown below the center of the are of the outlet passage, and the intake passage being in direct communicationwith the entire chamber between the casing and the pumping cylinder, giving the latter free and unobstructed movement about its pivotal bearing. It is, therefore, proposed that the pumping cylin- 'der, having a greater discharge pressure area above than below the pivotal bearing as herein shown, will be caused t'o'oscillate between its eccentric pumping position and its concentric zero pumping position against a predetermined external pressure by a slight increase or decrease of the discharge pressure inside the umpmg cylinder as distinguished "from' those pumps wherein thedischarge pressure is exerted externally thereof.

j The full nature of the invention will be understood from the accompanying drawings and the following description and claim:

Fig. 1 is a. front elevation of the!) "pwith the frontplate removed and showing the pumping cylinder in eccentric/relation to the frotor for full capacity pumping action, a portion being'in section. V

Fig. 2 is a centralvertical section through the pump with the pumping cylinder in its full capacity pumping position. T

Fig. 3 is the same as Fig. 1 with women in elevation and showing th ump ng cylinder. in its concentric idling'or' zero capacity position;

" In the drawings there is shown a pump having casing by the bolts 13 entering the threaded recesses Id. The end plate I2 is provided with a bearing portion I5 for receiving and mounting for rotation therein the drive shaft H5. The opposite end of the drive shaft I6 is supported for rotation in the bearing portion ll-of the end wall 'I l. The bearing portion l5 carries a threaded cap [8 for securing the packing la'about the shaft. Suitable driving means is applied to the shaft I6 in the usual manner for driving the pump.

Secured to the shaft I 6 for rotationthereby there is a rotor 20, said rotor being provided with a plurality of radial slots 2| for'slidably receiving therein the respective vanes 22. For maintaining said vanes in their outermost position, a pair of cylindrical rings 23 and 24 are mounted about the shaft within the opposite annular recesses 25 and 26, respectively, of the rotor. Said rings serve as bearing supports for the inner ends of the vanes 22 to maintain them at all times in their most outward permitted position.

The rotor and vanes are mounted to rotate within a pumping chamber provided by the cylinder 21. Said cylinder is mounted within the chamber 28 defined by the inner wall of the easing I0. Said inner wall is generally circular with one-half thereof concentric with the axis of rotation of the rotor and of substantially the same but slightly greater radius than the pumping cylinder. The opposed inner wall of the casing is eccentric to the axis ofrotation of the rotor, having its center of curvature spaced downwardly therefrom, in the position shownin the drawings, butlying in the plane extending through said axis of rotation bisecting said opposed wall sections of the casing. The pumpin cylinder has its peripheral surface relieved intermediate the sides thereof, as indicated at 29, said relief permitting free passage of fluid to the half bore 40 on the intake side of the pump. Thus, no fluid will be trapped in the chamber 28 by the cylinder in a manner to-resist its free action.

That portion of the cylinder located centrally of the concentric wall of the casing is provided with a projection. 30 shown herein as a screw head. One end of the compression spring 3| is seated about the projection 30 to bear against the cylinder; 21. Said spring extends through the bore of a nipple 32 extending radially outward from the casing, with the other end of said spring bearing against an adjustable screw cap 33.

The pumping cylinder 2'! is pivoted within the casing at the discharge side thereof for oscillatory movement between its eccentric pumping position, as shown in Fig. l, and its concentric idling position, as shown in Fig. 3. For this purpose the casing is provided with a series of half bores 34, there bein shown herein three of such bores. The cylinder 2! is similarly provided with a half bore 35. A rocker pin 36 is inserted to seat in the half bore 35 of the cylinder and a selected one of the half bores 34 in the casing. Thus, the cylinder is free to rock with a minimum of frictional resistance from its eccentric position of Fig. l to its concentric position of Fig. 3.

The pumping chamber defined by the cylinder 2! is provided with an outlet 3! and an intake 38. The outlet 31 is in communication with an arcuate outlet passage 39 formed in the back wall I l of the casing. The intake 38 is in communication with a half bore 46 extending transversely of the casing wall and opening therethrough to the chamber 28. At the back of the half bore an arcuate intake passage M is provided communieating therewith. Said arcuate intake and outlet passages have their ends approaching each other but in spaced relation to provide the necessary dam between the intake and outlet sides of the pumping chamber.

In operation, the spring 3! is set to exert a predetermined external pressure against the cylinder 21 in a direction to seat it against the eccentric wall of the casing, as shown in Fig. 1. In this position the cylinder will be positioned eccentrically with respect to the axis of rotation of the rotor so that the pump will operate under full capacity, Upon said cylinder being forced about the rocker pin 36 by the discharge pressure inside its pumping chamber, and said rocker pin being located below the center of the arc of the outlet passage 39, said cylinder 2T will be urged toward its concentric position against the predetermined pressure of spring 3! As the discharge pressure inside the pumping chamber becomes greater the pumping capacity will decrease. The differential pressure between the inside and outside of the pumping cylinder extends over that internal surface of the cylinder herein illustrated as defined by the distance between those vanes embracing the arcuate outlet passage 39. The low pressure area of said cylinder is slightly greater than the arcuate intake passage 33, the high and low pressures being separated by the vanes 32 passing between these passages. By locating the rocker pin 36 below the center of the pressure area (i. e., offset away from the application of the external force) a greater force will be exerted over that internal area of the cylinder above the rocker pin than below it. This greater force being above the rocker pin will; therefore, urge the cylinder upwardly against the tension of the spring 3|, from its eccentric position of Fig. 1 toward its concentric position of Fig. 3.

Therefore, any change in the pump discharge conditions will react directly on the inner peripheral surface of the pumping cylinder rocking it about its pivotal mounting to a more concentric or eccentric position relative to the pump rotor to re-establish the balance predetermined by the external force of the spring acting upon the cylinder. Since the hydraulic forces act directly inside of the pump cylinder, the mechanism is extremely sensitive and very simple. The serious defects of fluid shock pressures with resulting fluctuations encountered in that type of pump designed to maintain pump balance through external hydraulic pressures on the pumping cylinder are entirely eliminated. Additionally, its inherent sensitivity to discharge conditions results in greater life of its driving mechanism and greater hydraulic efficiency because the input torque is always at a minimum.

At the maximum desired pressure the cylinder will be rocked to its concentric position, as shown in Fig. 3, in which position the pumping capacity will approach zero. However, should the diiferential pressure within the pumping chamber fall while the pump is idling or in the zero capacity position, the tension of spring 3| will cause the cylinder to be moved sufliciently to increase the capacity until the predetermined pressure is regained. Therefore, the desired fluid pressure will be maintained at all times, irrespective of discharge conditions. It will be observed, therefore, that through the control of a predetermined pressure medium in the form of the spring 3| and within the capacity of the pump, such predetermined pressure will be at all times maintained irrespective of restricted discharge or back pressure, and by reason of the practical elimination of friction in the movement of the cylinder and free passage of fluid thereabout during its rocking movement, the sustained pressure will remain substantially constant and without material fluctuation.

Due to the unresisted rotation of the rotor and vanes when in the idle or zero capacity position of the cylinder, Fig. 3, a minimum of frictional resistance will develop so as to avoid any heating of the pump even though the outlet may be closed and the pump operating at full speed. The above characteristics of the pump are particularly desirable and important in high speed pumps of this character, wherein a predetermined pressure maintenance is desired.

Whereas the invention has been shown and described herein as applied to a pumping mechanism for converting mechanical power into fluid power, it is also applicable to the conversion of fluid power into mechanical power. In the latter case, it will be apparent that the shaft l6 becomes the driven member instead of the driving member, and the outlet conduit II! becomes the intake from a source of fluid power. In so utilizing the pump it may thereby be caused to drive the shaft IS with a constant output torque irrespective of fluctuations in the fluid driving power.

The invention claimed is:

In a rotary pump of the vane type, a pump casing having opposed inlet and outlet fluid passages therein, a floating pump cylinder pivotally mounted within said casing, said fluid passages communicating with the interior of said pump cylinder, a bore connecting said inlet passage with the space between said cylinder and casing extending substantially entirely about said cylinder, a rotor carried by said casing rotatable within said cylinder, an external pressure medium acting on said cylinder for biasing it toward its eccentric position under a predetermined force, and a pivot member mounting said cylinder peripherally thereof withinsaid casing on the opposite side thereof from said inlet passage and bore offset from the diametric plane transverse to the direction of force exerted by said external pressure medium and on the opposite side of said plane therefrom, said pump being characterized in that the said inlet passage opposite the pivotal mounting is in unobstructed communication with the space substantially entirely surrounding said cylinder to eliminate external resistance to the rocking movement thereof, and the fluid passage adjacent said pivotal mounting is in communica tion solely with the interior of said cylinder, the effective pressure area of said last-mentioned passage within said cylinder being greater on that side of the pivotal mounting towards said external pressure medium than on the other side thereof.

SIGURD HAUGDAHL.

REFERENCES CITED The following references are of record in the file of this patent: 

